Add AccessibilitySnapshotColorBlindness to README (pointfreeco#462)

Author: Sherlouk

README.md

@@ -207,6 +207,8 @@ end
 
   - [AccessibilitySnapshot](https://github.com/cashapp/AccessibilitySnapshot) adds easy regression testing for iOS accessibility.
 
+  - [AccessibilitySnapshotColorBlindness](https://github.com/Sherlouk/AccessibilitySnapshotColorBlindness) adds snapshot strategies for color blindness simulation on iOS views, view controllers and images.
+
 Have you written your own SnapshotTesting plug-in? [Add it here](https://github.com/pointfreeco/swift-snapshot-testing/edit/master/README.md) and submit a pull request!
 
 ## Related Tools